Improving UNIX server performance

Methods of improving UNIX server performance include adjusting disk and memory requirements and disk i/o tuning, and employing console and database logging.

Disk and memory requirements

When a UNIX system runs Domino® server software, the server must have enough disk space for program and data files and enough memory to handle swapping and the number of processes.

On Linux systems that are used for mail servers or applications where more than a few hundred databases are to be opened at one time, it is advisable to increase the file limit from its 1024 default value. You can modify this value by editing the file /etc/security/limits.conf. The entry should be for the nofile item.

		@notes		soft	nofile	60000		
@notes		hard	nofile	80000

In this example, the limit is set for a group in which the user who is running Domino® is a member. The limit can also be set, if desired, to the user who is running Domino®. The soft and hard values in this example may vary to meet the needs of your system, as long as they are large enough to stay under the file limit.

Other memory and network tuning parameters on Linux that help Domino® run more efficiently are set by a program which automatically runs at the startup of the Domino® server.

Disk I/O tuning

Maintaining multiple file systems for operating system files, swap space, transaction logs, and data improves overall server performance.

Use RAID 0+1 hardware for the disk drives on which the data files reside. Use multiple smaller disk drives instead of a few large disk drives for Domino® data. Domino® does not perform simple predictable sequential reads; therefore, disable Read Ahead Cache and enable Write Cache.

Keeping swap space on its own separate striped volumes improves server performance at high loads. The transaction logs should always be on the most reliable and highest performing disk subsystem available to the system hosting the Domino® server. Transaction logging must be on its own disk drives for improved server restart time, reliability, and availability. The logged transactions are written to disk as fast serial writes to a sequential file that is of configurable size in 4K blocks.

Console and database logging

To improve server performance, limit the amount of information that is logged to the log file (LOG.NSF) and the console.